It is known in the packaging industry to utilize induction heating techniques to form a tamper-proof seal over the outlet of a container. Commercially available equipment exists for this purpose. One such piece of equipment is the Lepak cap sealing generator which employs an induction coil to generate an electromagnetic field. This equipment is manufactured by Lepel Corporation, Maspeth, N.Y.
The container to be sealed has the outlet structure thereof exposed to the electromagnetic field with a seal element disposed over the outlet of the container. In particular, the seal element includes an aluminum disc with a thermoplastic material coated on a single side thereof. Conventionally, the disc is interference fitted into a screw cap or other well known type of cap with the coated side of the disc exposed. When the cap is screwed or otherwise positioned into place, the coated side will engage the container outlet structure.
The layer of polyester or the like is melted when the aluminum disc is subsequently heated up under the influence of the induction coil. This serves to seal the disc to the outlet structure of the container when exposure to the induction coil ceases and the thermoplastic material hardens.
The cap may be readily removed and replaced relative to the sealed outlet structure since there is no bonding which occurs between the seal and cap.